Keeling Curve Diagnosis

Sat, 07/26/2008 - 3:03pm  Alan Griffith

General Instructions for Coding DQC Responses

Responses to DQC questions can be grouped into three general categories; Informal, Mixed or Scientific. These three categories encompass a wide range of reasoning abilities, but all three categories are common among college students. The table below describes the general types of responses that would be associated with each level of reasoning. In addition, the levels of reasoning are assigned a numerical value for coding purposes. Codes 2-4 are used for responses that attempt to answer the question, while codes 1a-1e are reserved for missing responses or those that provide no information about student reasoning. Mixed reasoning presents itself in several different ways, thus level 3 answers are divided up into subcategories to reflect different types of responses.

Accounts of processes describe transformation? of reactants into products in ways that conserve atoms at the atomic-molecular scale and mass at larger scales.

Forms of energy are clearly identified and distinguished from forms of matter.

Energy transformation described in ways consistent with energy conservation.

3

Mixed reasoning

Partially successful attempts to connect scales, but with some inappropriate use of macroscopic ideas at other scales

Less than completely successful attempts to conserve matter. Reactants and products described as material kinds, but atoms not traced through chemical processes and matter-energy transformations may be used as a “fudge factor.)

Energy is recognized as a distinct entity, but sometimes in ways that do not clearly distinguish energy from matter (e.g., glucose, ATP) and/or conditions (e.g., temperature).

Accounts fail to conserve energy.

2

Informal reasoning

No attempt to make connections across scales for questions posed at macroscopic scale

Inappropriate use of macroscopic scale ideas at other scales

Material inputs or needs and products or results are mentioned, but not in ways that clearly distinguish matter, energy, and conditions.

No indication that the student is reasoning about transformation of matter: no account of how material inputs are transformed into results.

“Energy” used in an informal sense as something that makes events happen.

No clear distinction between energy sources and other needs or inputs.

1a

Missing data (e.g. responses or codes lost after exam was taken and coded)

1b

Student did not reach question

1c

Student skipped question

1d

I don’t know or equivalent

1e

Nonsense answer that is not responsive to question

These general ideas for coding above are applied to each individual question below to provide specific details for how to code each question. Still, you will find that the specific coding rubric for each question does not list every possible answer that you might see. In these cases, refer back to the general rubric above, and try to be as objective as possible. You will undoubtedly find responses that don’t quite fit a specific category, but seem to be in between. For these scenarios, we suggest that you assign a 2.5 or 3.5 code to the student.